1. Field of the Invention
The invention relates to an optical instrument, more particularly to an optical instrument including an axis-adjustable optical device.
2. Description of the Related Art
As shown in FIG. 1, a conventional telescope is an optical instrument that incorporates both digital recording and distance measuring functions. The conventional telescope includes a main body 10, and first, second and third optical devices 11, 12, 13.
The main body 10 includes a mounting seat 101 that extends upwardly.
The first optical device 11 has telescopic and laser-emitting functions. The first optical device 11 is coupled to the main body 10, and has a first optical axis (I1). The first optical device 11 includes a first objective lens unit 111 to be disposed to confront a target object, a first ocular lens unit 112 disposed opposite to the first objective lens unit 111, and a laser-emitting module 113 disposed adjacent to the first ocular lens unit 112.
The second optical device 12 is capable of sensing images and converting the images sensed thereby into digital signals. In other words, the second optical device 12 has image capturing functionality. The second optical device 12 is mounted to the mounting seat 101 of the main body 10, and has a second optical axis (I2).
The third optical device 13 has laser reception capability. The third optical device 13 is coupled to the main body 10, and has a third optical axis (I3). In particular, the laser emitted by the first optical device 11 is reflected by the target object. The reflected laser is received by the third optical device 13 in order to calculate the distance between the target object and an observation site at which the conventional telescope is located.
Since the first optical device 11 has telescopic and laser-emitting functions, the second optical device 12 is capable of sensing the image of the target object and converting the image into its corresponding digital signals, while the third optical device 13 is capable of receiving the laser reflected by the target object, the first, second and third optical axes (I1), (I2), (I3) are required to be parallel to each other such that the first, second and third optical devices 11, 12, 13 have the same angles of incidence with the target object and so as to avoid offsets. Therefore, in order to acquire accurate and consistent observations, image capturing, and distance measurements related to the target object, the conventional telescope requires axis adjustments prior to being released from the factory.
However, during actual manufacturing and axis adjustment processes, the following problems are encountered due to the structure of the conventional telescope, especially with the second optical device 12:
Lots of uncertainties are present during the manufacturing and assembly process of the conventional telescope, such as manufacturing tolerances in the mounting seat 101 and the second optical device 12, and displacement offsets between the mounting seat 101 and the second optical device 12 that occur during coupling, etc. These can affect the parallel relation of the second optical axis (I2) with the first and third optical axes (I1), (I3).
Since the mounting seat 101 is fixed on the main body 10, and since the second optical device 12 is mounted to the mounting seat 101, it is difficult to perform axis adjustments. In addition, after the second optical device 12 has been mounted to the mounting seat 101, it is required to dismount the second optical device 12 from the mounting seat 101 if the first, second and third optical axes (I1), (I2), (I3) are not parallel in order to repeat the axis adjustment process, which is inconvenient and time-consuming.